Closed-Loop Recycling: Mechanical Recycling of Polypropylene Cups

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Closed-Loop Recycling: Mechanical Recycling of Polypropylene Cups

Popis výsledku v původním jazyce

The recycling of plastic products is an integral part of the life cycle of polymers. This work focuses on the mechanical recycling of polypropylene (PP) thermoformed cups used in the food industry. The prepared shredded flakes from the PP dairy products (e.g. yogurt) cups were used to produceregranulate in twin screw extruder. To maintain comparative quality, the virgin polypropylene, from which these cups are normally made, was also regranulated, as well as the same PP with 2 wt. % of titanium white (again based on the composition of the original cups). In addition, a 30% blend ofrecycled and pure PP was also prepared. Materials were then analyzed by capillary rheometry, wide angle X-ray scattering, differential scanning calorimetry, thermogravimetric analysis, spectrophotometry and mechanically tested by tensile and impact testing. It can be concluded that recycled PP shows slight decrease in viscosity, crystallinity and melting point, and a significant increase in crystallization temperature. Mechanical testing shows that the addition of recycled PP into virgin material significantly increases the impact toughness, while the recycled material alone does not show such a rapid improvement, and the tensile modulus and maximum tensile strength slightly decrease. The relative elongation decreases as well. The addition of 2 wt.% titanium white to the virgin material slightly increases the crystallization temperature and significantly promotes formation of b-phase, as well as increase in impact toughness.Thus, it plays a role of specific b-nucleating agent. All in all, the processing and performance properties of the recycled PP were found to be comparable to the virgin material while it is thus suitable for application to same products, i.e. thermoformed cups. The reuse of food cup recycled PP in new products is a simple and effective way to increase the circular economy of PP and reduce the cost of producing disposable packaging materials. However, the potential contamination of the material still needs to be eliminated. Logistics issues also remain open.

Název v anglickém jazyce

Closed-Loop Recycling: Mechanical Recycling of Polypropylene Cups

Popis výsledku anglicky

The recycling of plastic products is an integral part of the life cycle of polymers. This work focuses on the mechanical recycling of polypropylene (PP) thermoformed cups used in the food industry. The prepared shredded flakes from the PP dairy products (e.g. yogurt) cups were used to produceregranulate in twin screw extruder. To maintain comparative quality, the virgin polypropylene, from which these cups are normally made, was also regranulated, as well as the same PP with 2 wt. % of titanium white (again based on the composition of the original cups). In addition, a 30% blend ofrecycled and pure PP was also prepared. Materials were then analyzed by capillary rheometry, wide angle X-ray scattering, differential scanning calorimetry, thermogravimetric analysis, spectrophotometry and mechanically tested by tensile and impact testing. It can be concluded that recycled PP shows slight decrease in viscosity, crystallinity and melting point, and a significant increase in crystallization temperature. Mechanical testing shows that the addition of recycled PP into virgin material significantly increases the impact toughness, while the recycled material alone does not show such a rapid improvement, and the tensile modulus and maximum tensile strength slightly decrease. The relative elongation decreases as well. The addition of 2 wt.% titanium white to the virgin material slightly increases the crystallization temperature and significantly promotes formation of b-phase, as well as increase in impact toughness.Thus, it plays a role of specific b-nucleating agent. All in all, the processing and performance properties of the recycled PP were found to be comparable to the virgin material while it is thus suitable for application to same products, i.e. thermoformed cups. The reuse of food cup recycled PP in new products is a simple and effective way to increase the circular economy of PP and reduce the cost of producing disposable packaging materials. However, the potential contamination of the material still needs to be eliminated. Logistics issues also remain open.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10404 - Polymer science

Projekt

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Návaznosti

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů